Inhalator comprising a dosage counting device

ABSTRACT

The invention is an inhaler for aerosolization of medicament with a unique dosage counter. The dosage counter has a first and second counting ring and a coupling device that interconnects the counting rings. The counter being advanced by a unique armature mechanism that is interconnected with the actuation mechanism of the inhaler to insure accurate counting of doses.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an inhalator for dispensing an aerosolcomprising a dosage counting device, a housing part, and an aerosoldispensing container displaceably arranged relative to the housing partalong its longitudinal axis.

2. Discussion of the Relevant Art

Such an inhalator is known from EP-A1-0 254 391. In these conventionalinhalators, an aerosol dispensing container is displaceably insertedinto a tubular portion of a housing part. The dispensing containercomprises a spraying tube which is guided out of a head area of thedispensing container, which spraying tube is inserted in a sealed mannerinto a spraying socket portion which is formed as a monolithic part ofthe housing. For dispensing a predetermined dosage of the medium storedin the dispensing container, a pressure force is applied to a bottomportion of the dispensing container and the container is briefly forcedinto the housing. Via the spraying tube inserted into the sprayingsocket a valve mechanism is opened for a moment and a predeterminedamount of the medium contained in the storage container is sprayed viathe spraying head. In a lateral area of the housing an indicator wheelis provided which is rotatably supported and which is rotated fartherfor each dispensing stroke of the inhalator by means of a step-down gearsystem by a minimal rotational distance. The indicator wheel is providedwith several filling level indicating marks which can be read by meansof a window portion for a successive rotation of the indicator wheel.When the dispensing container is almost completely emptied, acorresponding symbol is visible in the window, and this signalizes tothe user that the dispensing container is substantially completelyempty. By means of overfilling of the dispensing container at themanufacturing site by approximately 10 to 15%, it is ensured that uponreaching this end mark a sufficient amount of active substance is stillstored in the dispensing container.

The overfilling of the dispensing container carried out at themanufacturing site, in particular, when filling with comparativelyexpensive active substances, results in an increase in cost of theinhalator. Also, with regard to environmental protection considerationsan overfilling of the dispensing container to the degree that has beenconventional up to now appears to be problematic.

SUMMARY OF THE INVENTION

The invention has therefore the object to provide an inhalator fordispensing aerosols which is characterized by a high functionalreliability and a dosage counting device improved with respect toreadability and indication precision.

This object is solved according to the invention by an inhalator havinga first counting ring which is arranged coaxially to the longitudinalaxis of the aerosol dispensing container and is rotatable about thislongitudinal axis; a second counting ring which is arranged coaxially tothe first counting ring and can be directly coupled therewith and isrotatable relative thereto; counting ring switching device for rotationof the first counting ring upon actuation of the inhalator; and acoupling device for coupling the second counting ring with the firstcounting ring for a stepwise rotation of the second counting ringtogether with the first counting ring; wherein the counting ringswitching device has an actuation portion and a switching finger coupledtherewith, which for rotation of the corresponding counting ring can bebrought into engagement with control elements thereof.

In this way, it is possible in an advantageous manner to provide aninhalator which can be produced with respect to manufacturingtechnological aspects in a beneficial way and with which, as needed,each individual dosage stroke is counted and indicated. In addition tothe thus obtained reliable monitoring of residual filling amounts of theactive substance medium stored in the inhalator, it is moreover possibleto monitor the administration of the dosage aerosols in correspondencewith the prescription in an improved way. The inventively embodieddosage counting device makes possible, for example, counting from 0 toapproximately 200 of the individual dosage amounts. As an alternative tothis, it is also possible to provide the number arrangement on the twocounting rings such that dosage counting is possible in a descendingorder starting at the maximum stroke number. Counting can be performedsuccessively in the descending order, for example, starting with thenumber 200, wherein, for example, when the residual stroke number is≦50, in the indicator device a color marking, for example, in the formof a signaling bar, becomes visible which signalizes to the respectiveuser in a timely fashion that a new inhalator must be obtained.

The improvement of the indicating precision possible with the dosagecounting device according to the invention makes it possible to reducethe overfilling of the dispensing container, performed for safetyreasons, and to thus reduce the residual amount of active substance inthe dispensing container.

An advantageous embodiment of the invention with respect to aparticularly reliable further switching of the first counting ring isprovided in that the switching finger is spaced from the rotational axisand is positioned at a slant thereto. Accordingly, it is possible in akinematically beneficial way to bring the switching finger intoengagement with control elements provided at the counting ring and totilt the switching finger subsequently about a tilting axis whichextends substantially transversely to the longitudinal direction of theswitching finger. The positioning angle of the switching finger relativeto a radial plane defined by the counting ring is preferably in therange of 30 to 60°. In this connection, sufficiently large transportpaths of the switching fingers result in connection with favorable forceratios.

According to a preferred embodiment of the invention, the switchingfinger can be deflected out of an initial position into an end positionwhich is slanted relative to the initial position, wherein an engagementportion of the switching finger is forced already in the initialposition thereof in an elastically yielding fashion into an engagementposition with the first counting ring. Accordingly, in a reliable way itis ensured that each individual dispensing stroke of the inhalator iscounted by the dosage counting device.

An advantageous embodiment of the invention with respect to anespecially beneficial conversion of the dispensing stroke of thedispensing container of the inhalator into a further switching movementrequired for operating the dosage counting device is provided in that anarm part is provided that is coupled with the switching finger whereinthe arm part and the switching finger form an elbow joint mechanism.This ensures for still advantageous force ratios a comparatively longswitching finger transport distance so that it is possible to space thenumbers provided on the first counting ring so far apart from oneanother that only one individual number of the counting ring is visiblewithin the window portion, respectively.

The return force required for returning the switching finger can beprovided in an advantageous way by elastic deformation of the switchingfinger or of the actuator elements which are coupled with the switchingfinger. The switching finger is comprised advantageously of a plasticmaterial, preferably a thermoplastically formable plastic material.

An advantageous embodiment of the invention with respect to a reliableactuation of the switching finger is provided in that the arm part andthe switching finger are connected to one another by means of anactuation portion. The actuation portion forms in an advantageous way acontact surface facing a shoulder portion of the dispensing container ofthe inhalator, which contact surface, upon lowering of the dispensingcontainer within the context of a dosage stroke, is deflected from itsinitial position, in particular, is moved substantially in the axialdirection of the dispensing container.

The arm part and the switching finger are formed as a monolithic partaccording to a preferred embodiment of the invention. Advantageously, inthis embodiment the actuation portion is provided in the connecting areabetween the arm part and the switching finger. The movability of armpart and switching finger relative to one another results substantiallyfrom the elasticity of the material in the area of the correspondingtransition locations. The geometry of the transition portions isselected such that at least in the context of the determined number ofdosage strokes no considerable material fatigue or cross-sectionalweakness is caused in the corresponding connecting portions.

An advantageous embodiment of the invention with respect to anespecially high functional reliability of the dosage counting device isprovided in that at least the first counting ring, preferably also thesecond counting ring, and in a particularly advantageous way also theswitching finger are made of POM. The remaining components of theinhalator can be made of comparatively inexpensive plastic materials,such as, for example, polystyrene or polyethylene or other, preferablythermoplastically deformable, plastic materials.

An embodiment of the invention which is especially advantageous withrespect to an especially compact and functionally reliable configurationof the dosage counting device is provided in that the switching finger,the actuation portion and the arm part extend substantially arc-shapedabout the rotational axis of the first counting ring. The radius of thisarc corresponds advantageously substantially to half the diameter of theshoulder formed on the dispensing container. In this way, it isadvantageously possible to arrange the counting ring switching devicedirectly in the area of the dispensing valve of the inhalator. In thisway, it is advantageously possible to form a housing portion providedfor guiding the dispensing container of the inhalator by a separatelyformed tubular element which is placed onto the mouthpiece of theinhalator.

An advantageous embodiment of the invention with respect to a reliablecounting of the individual dosage strokes is provided in that a reversemotion check device is provided which has a locking pawl which engages,at least upon further transport of the first counting ring by onecounting step, a correspondingly formed engagement portion provided onthe counting ring.

As an alternative, or also in combination with such a locking pawl, itis also possible to prevent rotation of the first counting ring counterto the counting ring switching direction by a frictional lockingmechanism. The counting ring switching device; and, advantageously, alsothe reverse motion check device are formed according to a special aspectof the present invention such that they count each dispensing or dosagestroke.

In an advantageous way, the switching mechanism is formed such that thefirst counting ring is actuated and rotated farther even when adispensing stroke has been performed only incompletely. An advantageousembodiment of the invention with respect to an especially easy-runningconfiguration of the reverse motion check device is provided in thatseveral locking pawls are provided which can be brought into engagementwith corresponding engagement portions formed on the first countingring, wherein the individual locking pawls are arranged in a staggeredarrangements to one another such that these locking pawls are each indifferent engagement states.

The length of the arm part and the length of the switching fingers aswell as the position of the arm part and of the switching finger areadjusted such that upon displacement of the actuating element by apredetermined travel stroke the engagement portion of the switchingfinger is displaced in the circumferential direction of the firstcounting ring by a travel distance whose length is substantiallyidentical to the step length of a scale provided at the periphery of thefirst counting ring. In this way, it is possible advantageously todisplay the number combination required for the indication of eachindividual counting step in a uniquely defined way.

An advantageous embodiment of the invention with respect to anespecially reliable counting and indication of the individual dosagestrokes is provided in that the scale of the first counting ring has thenumbers of 0, 1, 2 . . . to 9, wherein these numbers are provided withidentical peripheral division on the periphery of the first countingring. These numbers can be, for example, applied by screen printing ontothe counting ring. However, according to an especially preferredembodiment of the invention, the scale is burned by means of a laserwriting method directly into the plastic material of the counting ring.

Also, the scale of the second counting ring has in an advantageousmanner the numbers 0, 1, 2 . . . to 9. The application of the numberingof the second counting ring can be carried out in the same way asexplained above with respect to the first counting ring.

An advantageous embodiment of the invention with respect to counting acomparatively large number of strokes is provided in that the scale ofthe second counting ring has the numbers 0, 1, 2 . . . to 20. In thisway it is advantageously possible to count with only two counting ringsa total of 200 dosage strokes. In particular, in this embodiment on thefirst counting ring the series of numbers 0, 1, 2 . . . to 9 is arrangedseveral times in sequence, in particular, 2 to 3 times. This shortensconsiderably the transport distance for further switching of the firstcounting ring.

The coupling device for coupling the second counting ring with the firstcounting ring for a step-wise rotation of the second counting ringtogether with the first counting ring comprises advantageously a tonguewhich is formed on the first counting ring and which is elasticallydeflectable and can be brought into direct engagement with an engagementportion of the second counting ring. This tongue is deflected accordingto a preferred embodiment of the invention by a contact nose that isstationarily arranged relative to the first counting ring whichmaintains the elastically deflectable tongue in engagement with thesecond counting ring across an angle interval which corresponds exactlyto the step angle for further switching of the second counting ring. Forrealizing corresponding gear ratios, if needed, several such contactnoses can be formed on a component of the inhalator which isstationarily arranged relative to the first counting ring. If needed, itis also possible to form several elastically deflectable tongue elementson the first counting ring which are designed to be brought into directcontact with the second counting ring.

An advantageous embodiment of the inhalator with respect to anespecially reliable operation of this coupling device is provided inthat the second counting ring comprises a bearing portion which isinserted into the first counting ring so as to be rotatable or is placedonto the first counting ring. By providing corresponding circumferentialgrooves and engagement portions between the two counting rings, it ispossible to support the two counting rings so as to be rotatablerelative to one another and to prevent an axial pulling-apart of the twocounting rings. The position of the: first counting ring relative to thecontact noses can be maintained in an advantageous way by acircumferential groove provided on the first counting ring.

The rotation of the second counting ring counter to the switchingdirection is advantageously prevented by an additional reverse motioncheck device.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and features of the invention result from the followingdescription of a preferred embodiment in connection with the drawing. Itis shown in:

FIG. 1 a longitudinal sectional view of an inhalator with mouthpiece anddisplaceably arranged dispensing container,

FIGS. 2a, 2 b, and 2 c a schematic representation for illustrating thetransport mechanism of the counting ring switching device provided inthe inhalator according to FIG. 1,

FIGS. 3a and 3 b a schematic illustration for a more detaileddescription of a preferred geometry of the switching finger, anactuation portion, and an arm portion,

FIGS. 4a, 4 b, and 4 c axial sectional views of the first and the secondcounting rings for explaining the function of the coupling device fordirect coupling of the first and second counting rings,

FIG. 5 a longitudinal section of a cover portion with integratedswitching finger as well as integrally formed reverse motion checkdevice,

FIG. 6 a radial section view along the line A—A in FIG. 5 for explainingthe configuration of the reverse motion check device, and

FIG. 7 a simplified side view of the inhalator according to FIG. 1 witha substantially rectangularly formed reading window aligned along thelongitudinal axis of the inhalator.

DESCRIPTION OF PREFERRED EMBODIMENTS

The inhalator illustrated in a simplified way in FIG. 1 for dispensingan aerosol comprises a dispensing container 1 slidably arranged along anaxial direction and the guiding shaft 2 provided for supporting thedispensing container 1 which is placed in a fitting way onto acorrespondingly formed connecting portion of an angular member 3.

A spray nozzle device 4 is arranged in the angular member 3 and isformed in a pin portion 5 formed as a monolithic part of the angularmember 3. In this pin portion 5 a dispensing tube 6 of the dispensingcontainer 1 is inserted in a sealed fashion. The dispensing tube 6 isreceived yieldingly in the axial direction in the head area 7 of thedispensing container 1 and is pre-tensioned by a spring device (notvisible) such that the dispensing container 1 is forced via thedispensing tube 6 away from the pin portion 5.

In the upper area of the guide shaft 2 a depression 8 is provided fromwhich a bottom portion 9 of the dispensing container 1 projects. Byapplying a pressure force onto this bottom area 9, the dispensingcontainer 1 can be moved toward the pin portion 5 as is indicated by thedash-dotted line in a simplified fashion. As soon as the dispensing tube6 contacts the contact surface formed correspondingly on the pin portion5, the dispensing tube 6 is forced into the dispensing container 1 andcooperates with a valve mechanism via which a pre-determined amount ofthe medium stored in the dispensing container 1 can flow out of thecontainer and can flow via the dispensing tube 6 and the spray nozzledevice 4 and from there into a intake area 10 formed in the angularmember 3. This insertion movement, which is referred to in the followingas dispensing stroke, of the dispensing container 1 is counted by adosage counting device 11.

The dosage counting device 11 comprises for this purpose a firstcounting ring 12 and a second counting ring 13. The first counting ring12 and the second counting ring 13 are rotatably arranged relative toone another. The second counting ring 13 has a rotational bearingportion which is inserted into a corresponding opening area of the firstcounting ring 12.

The first counting ring 12 and the second counting ring 13 are arrangedcoaxially relative to the longitudinal axis X of the dispensingcontainer 1. The two counting rings 12, 13 are rotationally arranged ina tubular portion of the angular member 3. On the outer circumferentialsurface of the two counting rings 12, 13, numbers are provided in a waywhich will be explained in the following in more detail which numberscan be read via a window opening 14 which is formed in the angularmember 3.

The embodiment of the inhalator illustrated in FIG. 1 has a secondcounting ring arranged approximately at the level of the shoulder 15formed on the receiving container 1. The second counting ring 13 issized with respect to its inner diameter such that the shoulder 15 ofthe dispensing container 1 can penetrate by a travel stroke,corresponding to the dispensing stroke length, into the second countingring 13.

In an annular space provided between the two counting rings 12, 13 andthe head area 7 of the dispensing container, a counting ring switchingdevice 16 is provided which rotates the counting ring 12, arrangedcoaxially to the dispensing container 1, by a certain angular distancefor each dispensing stroke.

The counting ring switching device 16 is formed in the illustratedembodiment as a monolithic part of the cover portion 17 which isinserted into the angular member 3. The cover portion 17 forms a bearingportion which extends substantially annularly about the longitudinalaxis X on which the second counting ring 13 is supported.

On the cover portion 17 a reverse motion check device for locking therotational movement of the counting rings 12, 13 in the counterdirection is provided as a monolithic part, respectively. The coverportion 17 is furthermore provided with a contact nose which forms partof a coupling device, to be explained in the following, for directcoupling of the two counting rings 12, 13.

The counting ring switching device is arranged within the two countingrings 12, 13 such that an actuation portion 19 thereof can be broughtinto contact with the shoulder provided on the dispensing container 1.

The function of the counting ring switching device will be explainedwith the aid of the FIGS. 2a, 2 b, 2 c. The counting ring switchingdevice 16 illustrated in FIGS. 2a, 2 b, and 2 c comprises a gear member,referred to in the following as a switching finger 20. In theillustrated embodiment, it is coupled by the actuation portion 19 withan arm part 21. In the illustrated embodiment, the switching finger 20,the actuation portion 19, and the arm part 21 are formed together as amonolithic part, and, as a result of the own elasticity of the plasticmaterial employed here, they are moveably coupled with one another.

The arm part 21 has a stationary end facing away from the actuationportion 19 by which the entire joint mechanism, formed by the arm part21, the actuation portion 19, and the switching finger 20, is supportedin the circumferential direction of the first counting ring 12.

In the illustrated arrangement, the arm part 21 and the switching finger20 form an elbow joint mechanism. By a gradual suppression of theactuation portion along the indicated longitudinal axis X of thedispensing container 1, the arm part 21 and the switching finger 20 arepivoted gradually into the final position illustrated in FIG. 2.Relative to a projection surface perpendicular to the axis X adisplacement results between the projection of the position of themovable end of the arm part 21 with respect to the projection of theposition of this end in the end position. According to thisdisplacement, the actuation portion is moved in the circumferentialdirection of the first counting ring. Also, the switching finger 20 ispivoted upon suppression of the actuation portion so that, as a whole,in this connection an elongation of the projection of the switchingfinger 20 in the projection surface perpendicular to the aforementionedlongitudinal axis X results. Since the switching finger 20 with the endportion facing away from the first counting ring 12 is also coupled withthe actuation portion, an addition of the displacement strokes, achievedby pivoting of the arm part and of the switching finger 20, results. Fortransmitting the corresponding movement component, acting in thecircumferential direction of the first counting ring, onto the firstcounting ring, the switching finger 20 is provided with an engagementportion 22 which can be brought into engagement with the controlelements formed on the counting ring. By a corresponding movement of theengagement portion 22 of the switching finger 20 in the circumferentialdirection of the first counting ring 12, the first counting ring 12 istransported in the circumferential direction by a predetermined travelstroke as a result of the engagement with the control elements 23. Thispredetermined travel stroke corresponds substantially to the spacingbetween the two neighboring control elements 23. Since the actuationportion 19 is moved into a lower end position as a result of theshoulder of the dispensing container 1, the actuation portion 19, as aresult of the own elasticity of the arm part 21, will also spring backinto its initial position upon return movement of the dispensingcontainer 1 in the guide shaft 2. During this return movement theswitching finger 20, respectively, its engagement portion, bypass thecontrol element 23, which will come into contact with the latter duringthe subsequent counting stroke, and springs directly behind this controlelement 23 again into its engagement position. Upon a new suppression ofthe actuation portion 19, the engagement portion 22 of the switchingfinger moves the control element 23, formed on the first counting ring,again by a transport interval in the circumferential direction. Thenumber which is the successively arranged one on the circumferentialsurface of the first counting ring 12 now is moved into the windowopening 14.

In the illustrations according to FIGS. 2a, 2 b, 2 c the counting ringswitching device for switching the first counting ring is illustrated ina developed illustration.

In the embodiment illustrated in FIG. 1, the joint mechanism formed bythe arm part 21, the actuation portion 19, and the switching finger 20of the counting ring switching device, extends, as illustrated in FIG.3b, substantially arc-shaped about the longitudinal axis X of thedispensing container 1 (not illustrated in FIG. 3). By suppressing theactuation portion 19 illustrated in FIG. 3b a displacement of theengagement portion 22 of the switching finger 21 in the circumferentialdirection is achieved. As a result of the displacement of the engagementportion 22 of the switching finger 20 in the circumferential direction,the first counting ring 12 can rotate farther by a switching angle a inthe circumferential direction. In the case that on the outercircumference of the first counting ring 12 three number sequences ofthe numbers 0 to 9 are provided, the switching angle α is approximately12°. For such a switching angle, a sufficiently large spacing betweenthe neighboring numbers results for a diameter of the first countingring 1 corresponding to the diameter of the dispensing container 1 sothat an easy readability of the individual numbers in the window opening14 is ensured. The gear ratio between the first counting ring 12 and thesecond counting ring 13 is determined in correspondence to the number ofthe number sequences provided on the circumference of the first countingring 12. The required gear ratio between the two counting rings canadvantageously be achieved by the coupling device described in thefollowing in connection with FIGS. 4a, 4 b, 4 c.

The coupling device illustrated in different coupling states in FIGS.4a, 4 b, 4 c comprises a tongue element 24 which is formed as a unitarypart of the first counting ring 12. In the illustration according toFIG. 4a it is in a neutral position. A follower portion 25 is formed onthe tongue element 24. This follower portion 25 is designed to engageengagement projections 26 which are formed as a monolithic part with thesecond counting ring 13. In this connection, a contact nose 27 providedon the cover portion 17 is provided which forces the tongue element intoa coupling position in which the follower portion 25, provided on theend of the tongue element 24, engages the engagement projections 26 ofthe second counting ring 13 positioned directly adjacently. As soon as acorresponding engagement state is produced, the second counting ring 13is rotated together with the first counting ring 12 until the tongueelement 24 drops off the contact nose 27 so that the engagement statebetween the follower portion 25 and the corresponding engagementprojection 26 is canceled. As soon as this engagement state is canceled,the first counting ring 12 can be further moved by a certain travelstroke, independently of the second counting ring 13.

In FIG. 4b the tongue element 24 is forced into the aforementionedcoupling position by the contact nose 27, not visible in thisillustration. The length of the coupling stroke, identified by theletter b, is determined by the geometry of the contact nose 27.

In FIG. 4c the tongue element 24 is already returned into its initialposition and the engagement between the follower portion 25 and thecorresponding engagement projection 26 of the second counting ring 13 iscancelled.

The tongue element 24 provided in the illustrated embodiment is amonolithic part of the first counting ring 12 and is formed as asubstantially flat leaf spring element. With respect to the requiredmechanical properties of the tongue element as well as with respect toan especially high precision fit of the first counting ring 12, it ispreferably made of POM plastic material. In the here illustratedembodiment, the numbers 1 to 20 are arranged at the outercircumferential surface of the second counting ring 13. By means of thetwo counting rings 12, 13, 200 dosages can be individually counted inthis embodiment. With the two counting rings it is possible to providecounting up to 999. By employing a third counting ring, a count up to9,999 is possible. The coupling device for coupling a third countingring with the second counting ring corresponds in its designadvantageously to that between the first counting ring 12 and the secondcounting ring 13.

For preventing a rotational movement of the second counting ring 13relative to the first counting ring 12 counter to the transportdirection, determined by the coupling device 24, 25, 26 as well as thecontact nose 27, a reverse motion check device 29 is provided for thecounting rings 12 and 13 which can be brought into engagement withcorresponding catch portions. In the here illustrated embodiment, thesecatch portions of the reverse motion check device are formed in a simpleway by the engagement projections 23 and 26.

In FIG. 5 the cover portion 17 provided for the inhalator according toFIG. 1 and the first counting ring 12 placed thereon are illustrated onan enlarged scale. In the shown embodiment,, the reverse motion checkdevice 28, provided for preventing rotational movement of the firstcounting ring 12 counter to the counting ring switching direction,comprises a spring element 29 formed, as a monolithic part of the coverportion 17 which can engage catch projections 30 which are formed on theinner circumference of the first counting ring 12 and face the countingring rotational axis X. The special geometry realized in this embodimentof the spring element formed as a monolithic part of the cover portion17 can be seen in FIG. 6 showing a simplified radial sectional viewalong the line A—A.

As can be seen also in the illustration according to FIG. 5, the tongueelement 24, which is provided for direct further rotation of the secondcounting ring 13 (not illustrated), has a flat rectangular cross-sectionand projects from an inner circumferential wall of the first countingring 12 into an annular space provided between the first counting ring12 and the cover portion 17. This annular space is limited in its upperarea by a contact portion 31 which supports the second counting ring 13,not illustrated here, in the axial direction. The illustrated,coverportion 17 forms moreover a second contact portion 32 by which the firstcounting ring 12 is supported in the axial direction. With respect tothe fact that the first and second counting rings 12, 13 are supportedagainst one another in the axial direction as a result of the shoulderstructure illustrated in FIG. 1, the two counting rings 12, 13 are as awhole supported in the axial direction by the aforementioned first andsecond contact portions 31 and 32.

In the sectional view according to FIG. 5, the contact nose 27 providedfor deflecting the follower portion 25 provided on the end portion ofthe tongue element 24 is shown only in dash-dotted lines. The countingring switching device 16, provided as a unitary part of the coverportion 17, and, in particular, its arm part 21, are also shown only indash-dotted lines.

The configuration of the mentioned filigree structure of a coverportion, insertable into the main housing portion of the inhalator, isadvantageous with respect to manufacturing-technological aspects.However, it is principally also possible to eliminate the cover portion17 and to embody the reverse motion check device 28 for locking thereverse movement of the first counting ring 12 as well as the countingring switching device and the corresponding support portions forsupporting the first and second counting rings 12, 13 directly on, i.e.,as a monolithic part of, the angled member 3.

The division of the catch projections 30 provided on the first countingring 12, illustrated in a sectional view according to FIG. 6, ispre-determined such that the reverse motion check device locks the firstcounting ring 12 anew after each counting step by means of the springelement 23. With a corresponding reduction in size of the catchprojections 30 and reduction in size of the spacing between thesuccessively arranged catch projections it is possible to make the catchintervals of the reverse motion check device smaller and to thus preventa rotational movement of the first counting ring even when the firstcounting ring 12 is not rotated by a complete counting step. With acorresponding configuration of the geometry of the spring element 29,the rotational resistance generated by the reverse motion check device28 can be maintained at a comparatively minimal value.

In FIG. 7 a side view (side view from the right) of the inhalatorillustrated in FIG. 1 is shown. The window opening 14 arranged on theside of the intake area 10 shows the number display. “200”. This numberdisplay is provided when by means of the first counting ring 12 thenumber “0” has been positioned in the window opening 14 and by means ofthe second counting ring 13 the number “20” has been moved into thewindow opening. For example, in the case of a descending count, thefirst counting ring 12 as well as the second counting ring 13 arerotated farther by an angular interval (α) about the longitudinal axis Xof the inhalator upon the next actuation of the inhalator. Accordingly,via the first counting ring 12, the number “9” and via the secondcounting ring 13 the number “19” reach the window opening 14.Accordingly, in the window opening 14 the number “199” is shown. Uponsubsequent actuation of the inhalator, the first counting ring 12 is nowfurther rotated and the number “8” is positioned in the window opening14. The window opening 14 now shows the number “198”. In connection withthe following dosage strokes, first the; first counting ring 12 isfurther rotated by single counting steps, respectively, until the number“1” enters the window opening 14 and in the window opening 14 the number“191” is shown. Upon the next actuation of the inhalator, as a result ofthe coupling mechanism illustrated in FIGS. 4a to 4 c, the firstcounting ring 12 is directly coupled with the second counting ring andthe first counting ring 12 together with the second counting ring 13 arefurther rotated by one counting step. Accordingly, the number 0 providedon the periphery of the first counting ring and the number “19” at theperiphery of the second counting ring 13 are positioned in the windowopening 14. In the window opening 14 the number “190” is now shown. Assoon as the number “19” has reached completely the window opening 14,the coupling mechanism for the direct coupling of the first and secondcounting ring 12, 13 is returned into its release position and the firstcounting ring 12 during the next dosage strokes is rotated independentlyof the second counting ring 13 until the number “1” of the firstcounting ring 12 again reaches the window opening 14.

In order to provide a substantially identical division of the numbersequence on the first counting ring 12 and the second counting ring 13,the number sequence of 0 to 9 is provided twice on the outercircumference of the first counting ring 12. For a more narrow design ofthe window opening 14 relative to the circumferential direction of thecounting rings, on the second counting ring 13, for example, the numbers0 to 40 can be provided. With a corresponding adjustment of the gearratio between the first and the second counting ring 12, 13, forexample, by multiplying the number of contact noses 27, provided forfurther transport of the second counting ring, numbers of 0 to 400 canbe counted in a descending or ascending sequence with only two countingrings.

The invention is not limited to the aforementioned embodiments. Forexample, it is also possible to eliminate the cover portion 17 providedin the afore described preferred embodiment of the inhalator and to formthe corresponding functional parts integrally with the housing of theinhalator. If needed, aerosol-free active substances can also bedispensed with the described inhalator. For making available an evenlarger counting range, it is possible to provide a third counting ringwhich can be coupled by a corresponding coupling mechanism with thesecond counting ring.

What is claimed is:
 1. The inhalator for dispensing an aerosol,comprising: a dosage counting unit (11), a housing device (2,3) having astationary part (17), an aerosol dispensing container (1) arranged inthe housing device (2, 3) and slidable relative to the housing device(2, 3) in a direction of a longitudinal axis of the aerosol dispensingcontainer (1), a first counting ring (12) arranged coaxially to thelongitudinal axis (X) of the aerosol dispensing container (1) androtatable about the longitudinal axis (X), a second counting ring (13)arranged coaxially to the first counting ring (12) and rotatablerelative to the first counting ring (12), a counting ring switchingdevice (16) for rotating the first counting ring (12) upon actuation ofthe inhalator, a coupling device (24, 25, 26, 27) coupling the secondcounting ring (13) to the first coupling ring (12) for a stepwiserotation by a counting step of the second counting ring (13) togetherwith the first counting ring (12), wherein the counting ring switchingdevice (16) has an actuation portion (19) and a switching finger (20)coupled to the actuation portion (19), wherein the first counting ring(12) has control elements (23), wherein the switching finger (20)engages the control elements (23) for rotation of the first countingring (12) in a counting direction, and wherein the switching finger (20)is spaced from the longitudinal axis (X) and is arranged at a slant tothe longitudinal axis (X) and engages the control elements (23) axially,further comprising an elastically yielding arm part (21) coupled withthe switching finger (20) via the actuating portion (19) such that thearm part (21) and the switching finger (20) form an elbow jointmechanism, the arm part (21) being supported on the stationary part(17).
 2. The inhalator according to claim 1, wherein the switchingfinger (20) has an engagement portion (22) and is configured to bedeflected from an initial position into an end position slanted relativeto the initial position, wherein in the initial position the engagementportion of the switching finger (20) is elastically yieldingly forcedinto an engagement position with the first counting ring (12).
 3. Theinhalator according to claim 1, wherein the arm part (21) and theswitching finger (20) are connected to one another by the actuationportion (19).
 4. The inhalator according to claim 1, wherein the armpart (21) and the switching finger (20) are formed as a monolithic part.5. The inhalator according to claim 1, wherein the arm part (21) and theswitching finger (20) are comprised of a plastic material.
 6. Theinhalator according to claim 1, wherein the actuation portion (19) isguided in a direction substantially parallel to a rotational axis of thefirst counting ring (12) and wherein the arm part (21) forms a springelement forcing the switching finger (20) into the initial position. 7.The inhalator according to claim 1, wherein the aerosol dispensingcontainer (1) has a shoulder and wherein the actuation portion (19) hasa contact surface configured to contact the shoulder of the aerosoldispensing container (1).
 8. The inhalator according to claim 1, whereinthe switching finger (20), the actuation portion (19), and the arm part(21) extend substantially arc-shaped about a rotational axis (X) of thefirst counting ring (12).
 9. The inhalator according to claim 1, furthercomprising a reverse motion check device (28) for preventing arotational movement of the first counting ring (12) counter to thecounting direction.
 10. The inhalator according to claim 9, wherein thereverse motion check device (28) has a locking pawl.
 11. The inhalatoraccording to claim 1, further comprising a first scale providedcircumferentially on the first counting ring (12), wherein a length ofthe arm part (21), a length of the switching finger (20), and a positionof the arm part (21) and a position of the switching finger (2 a) areadjusted such that upon a displacement of the actuating element (19) bya predetermined travel distance the engagement portion (22) of theswitching finger (20) is displaced in a circumferential direction of thefirst counting ring (12) by a travel distance having a length matching astep length of the first scale.
 12. The inhalator according to claims11, wherein the first scale has a number sequence 0, 1, 2 . . . to 9.13. The inhalator according to claims 11, further comprising a secondscale provided on the second counting ring (13), wherein the secondscale has the numbers 0, 1, 2, . . . to
 9. 14. The inhalator accordingto 11, further comprising a second scale provided on the second countingring (13), wherein the scale of the second counting ring (13) has thenumbers 0, 1, 2, . . . 9, 10, 11, . . . 19 and
 20. 15. The inhalatoraccording to claim 12, wherein the number sequence 0, 1, . . . 9 isprovided multiple times.
 16. The inhalator according to claim 1, whereinthe second counting ring (13) has a bearing portion rotatably insertedinto the first counting ring (12).
 17. The inhalator according to claim1, wherein the second counting ring (13) has a bearing portion placedonto the first counting ring (12).
 18. The inhalator according to claim1, wherein the coupling device (24, 25, 26, 27) has a follower elementcoupled with the first counting ring (12).
 19. The inhalator accordingto claim 18, wherein the follower element is formed by an elasticallyyielding tongue element (24) formed as a monolithic part of the firstcounting ring (12).
 20. The inhalator according to claim 19, wherein thecoupling device has at least one stationary contact nose (27) fordeflecting the tongue element (24) such that the tongue element engagesthe second counting ring (13) over a circumferential lengthcorresponding to the counting step and rotates the counting ring (13) bythe circumferential length.
 21. The inhalator according to claim 20,wherein the second counting ring (13) has a toothing portion configuredto engage the tongue element (24).
 22. The inhalator according to claim20, wherein three of the stationary contact noses (27), spaced uniformlyfrom one another in the circumferential direction, are provided suchthat the second counting ring (13), upon a complete circumferentialrevolution, entrains the second counting ring (13) by three countingsteps.